Solution for this topic

1/ How can I also have this padding to the product page? When I add padding: 160px 0; to .single-product.postid-8594 .sh-titlebar it’s way too big.

To add padding to the product page try using the below CSS code. You can change the value 160 in the below code to change size of padding.

.single-product #page-container .sh-titlebar {
    padding: 160px 0;
}

2/ How can I add more then one? What’s the best way, let’s say 8595 and 8596 with the same image? Can I combine it to clean a bit my css ?

To use same image on the pages you can use CSS code as following.

.single-product.postid-8594 .sh-titlebar,
.single-product.postid-8595 .sh-titlebar,
.single-product.postid-8596 .sh-titlebar {
    background-image: url(//www.worldofpixels.be/wp-content/uploads/2016/03/pexels-photo-v270221.jpeg);
}

If you want to use same image on all product pages then use the below CSS code.

.single-product .sh-titlebar {
    background-image: url(//www.worldofpixels.be/wp-content/uploads/2016/03/pexels-photo-v270221.jpeg);
}